1. Field of the Invention
The present invention is related to the beneficiation of ores and is particularly related to beneficiation of magnesite ores by gravimetric or magnetic procedures.
2. Description of the Prior Art
Run-of-mine magnesite ores usually contain gangue material such as serpentines, dunites, pegmatites, silica, etc. Both the serpentines and dunites normally contain a small percentage of iron, which thereby enables a portion of the gangue to be separated out by a magnetic separation process. Generally, such ores are amenable to gravimetric methods of separation due to the difference in the specific gravities of the pure magnesite (Sp.Gr..perspectiveto.2.70 to 2.80 g/cm.sup.3) and the gangue (Sp.Gr. ranging from about 2.55 to about 2.65 g/cm.sup.3), and the most commonly used method of separation is the dense media process. Such ores are also amenable to concentration by flotation, but this is an expensive method, since it first requires grinding the ore to a fine mesh, and subsequently requires expensive methods for briqueting the ground concentrate to facilitate the firing thereof to produce a dead-burned magnesite.
Some ores are not amenable to gravimetric separation in any event because the magnesite contained therein is porous and has an apparent specific gravity (bulk density) which is very nearly the same as the gangue. These latter described ores are of course amenable to concentration by flotation, but as mentioned before, this procedure is generally very expensive.